The use of radioactive isotopes in research and medicine is a multi-billion dollar industry that serves nearly twenty million Americans each year in nuclear medical procedures. It also serves an essential function in the nation's nuclear security and nuclear research. Numerous reports extensively document the national need for research radioisotopes, especially for both beta/gamma particle emitters and alpha particle emitters.
67Cu is a valuable isotope with both beta and gamma emissions which are extremely useful for image-guided radiopharmaceutical therapy. Among other valued characteristics, it emits both therapeutic and imaging radiation and has been approved for trials with human patients. Even though the use of this isotope in radiopharmaceutical therapy is highly advantageous, research with 67Cu has been hampered by the limited availability of the isotope. The limited supply of certain 67 radioisotopes, including Cu, is a fundamental limiting factor in many biomedical research programs that are exploring targeted treatment with radioisotopes. The nation's supply of such isotopes is reliant upon a scant number of production facilities utilizing very few production processes.
Radioactive nuclides can be produced through radio-activation of a target using any radiation that carries sufficient energy to induce nuclear breakup. The vast majority of isotopes used in research are produced by research nuclear reactors. Aside from a paucity of such facilities, more than half of the research reactors involved in isotope production are forty years old or older. Accordingly, no robust sources of these isotopes exist in the Unites States today. Novel ways of producing research isotopes for medical and other purposes are necessary to address the issues of (i) the inability of reactors to produce certain isotopes, e.g., proton-rich isotopes, and (ii) the production of isotopes currently in short supply, and (iii) the potentially impending shortage of isotopes as ageing reactors are shut down.
One potential solution is to focus upon electron accelerators. When coupled to sub-critical assemblies, electron accelerators are capable of producing large quantities of both neutron-rich and proton-rich radioisotopes. High power electron accelerators are well suited for the production of some important isotopes for medical and industrial applications.
Accordingly, new methods of isotope production suitable for electron accelerators and corresponding new processing technologies are necessary in order to make more isotopes available for research and other applications.